Twin carb set up model 20 1958

fairbairn · Post by **fairbairn** » Sat Feb 14, 2009 2:55 am

I`m currently at the stage where i`m putting the bike back together and as a concequence i`m solving some little problems that just seem to appear. while working on the twin carb set up , i have noticed that there is a very small hole in the 2nd carb ( the one without a float ) the hole is on the top side of the float bowl , it looks as if it should be there ,i only noticed it as the carbs are flooding at present and so i saw petrol spurting out of this hole in the second carb , i`m working on the flooding issue and will sort it out, but does anyone know what this hole is there for? the carbs are 376`s many thanks Ian

smsxr05 · Post by **smsxr05** » Tue Feb 17, 2009 12:08 pm

Hi,
As far as i'm aware the 1958 M20 only has 1 carb. If your has been converted to twin carb then BOTH carbs should have a float.

fairbairn · Post by **fairbairn** » Tue Feb 17, 2009 1:53 pm

Hi Steve many thanks for your reply , yes the model 20 was produced with a single carb , however it was a standard type conversion to convert to twin carb and the second carb did not have a float , i can`t remember which of my books i read this in but remember coming across the article and felt at the time reassured as i had been questioning the set up for a while, i`ve spoken to steve at amc classic spares and he does not know why there would be a hole in the second carb but has advised me to contact the chap at Surrey cycles who may know , so i will let you know should i find out more many thanks Ian

fairbairn · Post by **fairbairn** » Tue Feb 17, 2009 2:15 pm

Hi Steve , just spoken to Neville at Surrey Cycles and the hole in the top of the carb is a airhole in order to prevent a vacuume developing between the carbs , it`s the same set up as on the ss 650 Horton , all the best Ian